Solid epithelial cancers account for over 10% of all deaths each year world-wide. This figure is expected to increase. Early-stage cancer diagnosis and subsequent complete surgical removal of the tumor offers the best chance for complete cancer cure. With early-stage tumor screening and diagnostics becoming more efficient, the bottleneck lies in efficient surgical management. Current surgical technology cannot precisely define the margins of a tumor, resulting in missed opportunities for life-saving treatment. Tumor residues may remain undetected and untreated until they grow to advanced stages, at which point both patient death rate and overall treatment costs can dramatically increase.
The diagnosis of a solid tumor typically involves (i) a screen via a blood test or mucosal smear (molecular diagnostics assays); (ii) gross tumor localization in the body typically by means of radiological imaging (e.g., PET, CT, MRI and ultrasound); and (iii) a visual inspection (e.g., endoscopy), and if necessary, the excision of a tissue sample (e.g., biopsy), and a subsequent pathologic examination.
The pathology laboratory analysis is crucial in the diagnostic process as it is often the basis for the final diagnosis at which the stage of the tumor is confirmed. The pathologist typically prepares thin tissue sections of a frozen or otherwise fixed tissue sample (e.g., a sample processed with formalin or paraffin) obtained during a diagnostic biopsy, then the pathologist examines the thin tissue sections under a microscope. The morphology of the tissue (e.g., cell size and cell arrangement) is the principal basis for distinguishing between healthy and cancer tissue, and for distinguishing between malignant and benign cancer tissue.
Because diagnostic techniques and cancer screens are improving, cancers are more frequently detected in the earlier stages. This gives oncology surgeons the opportunity to apply the most efficient and least invasive cancer treatment—complete surgical removal of the tumor.
If no metastases are present, minimally invasive surgical procedures can be used to remove the solid tumor. Typically, chemotherapy is not necessary for patients who undergo a complete resection of the tumor. However, a complete resection requires “tumor-free margins” of the resected tissue, meaning that no tumor cells are left behind in the patient.
Currently, there is no reliable means available to guide the resection of solid tumors. For certain indications, this results in the need to re-operate on many patients days after the initial operation when an analysis is obtained from the histo-pathology laboratory. Such follow-up surgical procedures usually lead to less favorable outcomes for the patient, psychological stress, and can roughly double treatment and hospitalization costs.
Healthcare institutions sometimes perform intra-operative frozen-section analysis (FSA) during certain tumor surgeries. Intra-operative FSA is a pathologic assessment of the resected tissue during ongoing surgeries. In spite of inherent problems, such as inferior sample quality when compared to standard paraffin-embedded histology, possible wrong diagnosis due to freezing artifacts (e.g., fatty tissue, like breast or brain tissue, is not suitable for rapid freezing), and tedious sample preparation (e.g., FSA needs to be planned ahead of surgery), long term studies show that intraoperative FSA can reduce the reoperation rate to 10% in the case of breast tumor resections.
However, intra-operative FSA requires the prolongation of operation time by at least 30 minutes, which, in addition to inconvenience for the patient and the clinical personnel, results in increased cost of the surgery and complications for operating theatre planning and management. Further, many tumor surgeries today do not include pathologic margin assessment, primarily due to the inconvenience and cost of a frozen section analysis. Thus, there is a need for a system for more efficient in-operating-theatre imaging of tissue.